问题描述

产生冲突的原因是因为 uvicorn 启动时候会解析命令行参数，而 argparse 也会解析命令行参数，导致冲突。
具体表现为，当使用 uvicorn 启动时候，argparse 获取不到参数。

即在代码中如果在启动了的 uvicorn 程序中调用了sys.argv[1:], 则会报错
在 argparse 中的参数列表初始化中有这么一段代码，也是导致报错的原因

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def parse_known_args(self, args=None, namespace=None):
    if args is None:
        # args default to the system args
        args = _sys.argv[1:]
    else:
        # make sure that args are mutable
        args = list(args)

解决方案

在初始化 argparse 时候，传入参数 [] 即可解决问题

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parser = argparse.ArgumentParser(add_help=add_help)
args = parser.parse_args([])

附上实际报错栈弹出日志

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ERROR:uvicorn.error:Exception in ASGI application
Traceback (most recent call last):
  File "/Users/asus/miniconda3/envs/testtest37/lib/python3.7/site-packages/uvicorn/protocols/http/h11_impl.py", line 366, in run_asgi
    result = await app(self.scope, self.receive, self.send)
  File "/Users/asus/miniconda3/envs/testtest37/lib/python3.7/site-packages/uvicorn/middleware/proxy_headers.py", line 75, in __call__
    return await self.app(scope, receive, send)
  File "/Users/asus/miniconda3/envs/testtest37/lib/python3.7/site-packages/fastapi/applications.py", line 211, in __call__
    await super().__call__(scope, receive, send)
  File "/Users/asus/miniconda3/envs/testtest37/lib/python3.7/site-packages/starlette/applications.py", line 112, in __call__
    await self.middleware_stack(scope, receive, send)
  File "/Users/asus/miniconda3/envs/testtest37/lib/python3.7/site-packages/starlette/middleware/errors.py", line 159, in __call__
    await self.app(scope, receive, _send)
  File "/Users/asus/miniconda3/envs/testtest37/lib/python3.7/site-packages/starlette/middleware/cors.py", line 84, in __call__
    await self.app(scope, receive, send)
  File "/Users/asus/miniconda3/envs/testtest37/lib/python3.7/site-packages/starlette/exceptions.py", line 71, in __call__
    await self.app(scope, receive, sender)
  File "/Users/asus/miniconda3/envs/testtest37/lib/python3.7/site-packages/starlette/routing.py", line 656, in __call__
    await route.handle(scope, receive, send)
  File "/Users/asus/miniconda3/envs/testtest37/lib/python3.7/site-packages/starlette/routing.py", line 259, in handle
    await self.app(scope, receive, send)
  File "/Users/asus/miniconda3/envs/testtest37/lib/python3.7/site-packages/starlette/routing.py", line 61, in app
    response = await func(request)
  File "/Users/asus/miniconda3/envs/testtest37/lib/python3.7/site-packages/fastapi/routing.py", line 227, in app
    dependant=dependant, values=values, is_coroutine=is_coroutine
  File "/Users/asus/miniconda3/envs/testtest37/lib/python3.7/site-packages/fastapi/routing.py", line 161, in run_endpoint_function
    return await run_in_threadpool(dependant.call, **values)
  File "/Users/asus/miniconda3/envs/testtest37/lib/python3.7/site-packages/starlette/concurrency.py", line 39, in run_in_threadpool
    return await anyio.to_thread.run_sync(func, *args)
  File "/Users/asus/miniconda3/envs/testtest37/lib/python3.7/site-packages/anyio/to_thread.py", line 34, in run_sync
    func, *args, cancellable=cancellable, limiter=limiter
  File "/Users/asus/miniconda3/envs/testtest37/lib/python3.7/site-packages/anyio/_backends/_asyncio.py", line 877, in run_sync_in_worker_thread
    return await future
  File "/Users/asus/miniconda3/envs/testtest37/lib/python3.7/site-packages/anyio/_backends/_asyncio.py", line 807, in run
    result = context.run(func, *args)
  File "./app/api/v1/face.py", line 14, in init_face_index
    return crud.init_face_index(index_name)
  File "./app/sql_app/crud.py", line 15, in init_face_index
    face_ = FaceRecognition(index_name=index_name, operate="index")
  File "./app/face_recognition.py", line 26, in __init__
    self.args = parser.parse_args()
  File "/Users/asus/miniconda3/envs/testtest37/lib/python3.7/argparse.py", line 1758, in parse_args
    self.error(msg % ' '.join(argv))
  File "/Users/asus/miniconda3/envs/testtest37/lib/python3.7/argparse.py", line 2508, in error
    self.exit(2, _('%(prog)s: error: %(message)s\n') % args)
  File "/Users/asus/miniconda3/envs/testtest37/lib/python3.7/argparse.py", line 2495, in exit
    _sys.exit(status)
SystemExit: 2